Light control fixture



Dec. 28, 1954 s. H. LEE

LIGHT CONTROL FIXTURE 2 Sheets-Sheet 1 Filed Nov. 14, 1949 INVENTOR, SHERMAN H. LEE.

ATTORNEVS.

Dec. 28, 1954 Filed Nov. 14, 1949 S. H. LEE

LIGHT CONTROL FIXTURE 2 Sheets-Sheet 2 INVENTOR, SHERMAN H. LE5.

ATTORNEYS United States Patent LIGHT CONTROL FIXTURE Sherman H. Lee, San Francisco, Calif., assignor of onehalf to Cepco, Inc., San Francisco, Calif., a corporation of California Application November 14, 1949, Serial No. 126,991

Claims. (Cl. 189-62) This invention relates to light control units of the louver type, adapted to be mounted below a light source and direct the light downwardly while preventing direct view of the light and glare from any normal point of view. Particularly the invention relates to such units as are intended to cover an entire ceiling.

Among the objects of the invention are to provide a light control system constructed in modular units which can be adapted to cover a ceiling of any area and sub stantially any shape; to provide a system wherein the modular units can be shipped in knocked-down form and erected at the site at which they are to be used; to provide a system wherein each unit is hinged so that it may be swung out of the way to permit access to the lights at any part of the main ceiling or roof above the fixture, or can, at will, be removed entirely for cleaning or any other pulpose; and, ancillary to the above mentioned objects, to-provide a form of construction for the modular units of the frame upon which the grids are hung which, when erected, are rigidly dimensioned so that the grids will swing freely, although closely fitted within the frame; to provide a grid frame which, while extremely light in construction and offering a minimum degree of interception to the infalling light, is itself rigidly dimensioned and resistant to distortion; and to provide a suspension system which can be accommodated to irregularities in the roof or other structure from which it is supported and hold the fixture level and free from distorting strains or stresses.

Referring to the drawings,

Fig. 1 is a perspective view of a number of modular units embodying my invention as suspended from a roof or ceiling, and illustrating generally the method of support of the system and the lighting fixtures to be controlled by it, and the freedom of hinging of the light con trol units themselves;

Fig. 2 is a detailed view showing an intermediate corner between four of the modular units of a hanger frame, and illustrating the method of assembly and support of said frame;

Fig. 3 is a plan view of a section of the grid frame, portions of the structure being cut away to show its construction;

Fig. 4 is a fragmentary vertical section through-the louver grid and frame, the plane of section being indicated by the lines 4, 4 in Fig. 3;

Fig. 5 is an exploded view showing another method of constructing the frame of the louver grid;

i Fig. 6 is a plan view of one modular unit of the struc ture, indicating the location of the hinge pins;

Fig. 7 is a plan view of a support saddle for holding the side members at an intermediate corner of the hanger Fig. 8 is a cross sectional view of the saddle of Fig. 7, the plane of section being indicated by the line 8, 8 in the former figure;

Fig. 9 is a plan view of the cover or clamp member fitting over the saddle of Fig. 7; 1

Fig. 10 is a cross sectional view of the clamp of Fig. 9; and

Fig. 11 is a cross sectional view through hanger and grid frames, showing a hinge pin.

To provide an adequate light control system of the louver type which will cover an entire ceiling a number of I rigidly determining its dimensions.

mutually incompatible factors must be reconciled. Practically, it is necessary to make the system in modulapunits ofistandardized size and shape, since the cost of tailoring and maintenance would be a long and expensive pro-v cedure, but, on the other hand, they must not be heavy and clumsy to handle since this again would lead to undue maintenance expense. Free access must be offered to the lights themselves to permit them to be serviced; which means that the grids must be readily removable, which again demands lightness of construction, but since they must fit accurately when in place they must be highly resistant to distortion. A maintenance worker caring for a lighting system of this type is always working overhead and frequently upon a ladder; therefore if the louver grid is to be removed entirely he must handle a structure of considerable size-say on the order of four feet squarewhich is essentially frail in construction and yet is clumsy and heavy, andthis presents accident hazards.

My invention obviates the necessity of complete removal, permitting the grids to be swung out of the way to give full access without ever requiring that their entire weight be lifted or that the worker descend a ladder carrying the same. Furthermore, since the grid frames can be made weighing half or less than half of those of the prior art the entire problem is greatly simplified.

Fig. 1 shows the general makeup of a section of a system comprising six modular units in accordance with my invention. A hanger frame comprising side memhers I and transverse members 1' is suspended from a roof or. ceiling by means of vertical hanger rods 3 secured at each corner of the hanger frame. Fluorescent or other lamps 5, mounted on fixtures 7, may be mounted directly on the ceiling or may be supported on stretcher bars (not shown) secured to the hanger rods, as circumstances dicrate.

The cross members 1 divide the rectangular hanger frame into similar rectangular units, preferably square, and within each of these square units is fitted a grid frame and louver assembly 11, each of the grid frames being supported in the hanger frame by two pairs of retractable pins positioned near the ends of opposite sides of the frame which engage holes in the frame members (as will be described later), the pins acting both as latches and hinges, so that when either pair is retracted the section can swing down upon the other pair of hinges as is shown in the figure. sary to provide only two pairs of pins, since the units can be rotated within the hanger frames to swing in any direction desired.

The detail of the hanger frames and their supports is be supported some considerable distance below the roof it may be made as long as desired.

Bolted or pinned to the lower end of the stem 15 is a tubular thimble 19, carrying, at its lower end, aninternally threaded bushing 21. is a screw 23, preferably provided with a lock nut 25 to maintain its adjustment within the bushing, and the lower or head end of the screw is provided with a deep slot forming a yoke 27 within which a universal link 29' is pivoted. The ends of this link are twisted to a 90 angle with respect to each other and the lower end of the link is in turn pivoted within a similar yoke 31, the bottom of which is threaded to form a cap nut.

The hanger frame is secured to the yoke or cap nut 31 by means of a screw 33 which also serves rigidly to secure the corner clamps holding the hanger frame together and The details of one of these clamps are shown in Figs. 7 to 10, inclusive. The clamp shown is an X type, designed foran intermediate junction of the frame where four units come together. Similar clamps of both L and T types are provided for the outer corners of the hanger frame and Patented Dec. 28, 1954 Since the grid units are square it is neces- Threaded into this bushing zg easmr for the intersections of cross members with the outer sides of the frame respectively; as it is believed thatthe structures of these will be apparent from that of the X clamp, they are not shown in detail.

The; clamp comprises a saddle member: having: rec+- tangularly disposed. arms 35 of. channel section,-. as is. A boss 37 projecting upward and. inwardly at the" junction of' the. arms 35' may be shown in:Figs. 7 and.8.

provided':to:form a recess for'the head of the'screw 33'. Alternatively, the screw 33 may be of the flat head. type and the saddle. merelycountersunk toreceive it.

Fitting over. the saddle is' a cover or clamp plate 39, conformingin shape-to the plan of the'saddle,.and providedwith-a downwardly. turned edge 41. This edge,- of

course, serves to. stiffen the entire clamp, but it'may be omitted with. the. exception. of the portions 43 at the endsofzeach armof' theclamp, since'this'part-actsas a lip. for positioning positivelyfthe channels forming the sides 1 and 1' of the hanger frame.

The'channels are preferably of aluminum, having ends whichiare milled downby'ani amountequal to the thick-. ne'ss' of. the material ofthe' hanger. saddlewithin which the channel sidemembers'rest, so that thelower surface of the-channel member and the saddle member are sub sta'ntia'lly: continuous. This'ismerelyv a refinement, however; channel members 1 may be formed of steel instead of: aluminum, and their outer dimensions, throughout,

maybe such asto permit'them to nest within the'saddle by. preference, they are all. alike. A tubular bushing 49' surrounds the screw 33, the length of this bushing being such that it permits the clamps to engage the channels firmlybut will not permit the screw to be setup so'tightly as t oi deform the'parts of the clamp.

The brackets- 13' are secured to the ceiling or'roof as nearly as possible vertically above the corners of the hanger frame units. The inaccuracies of building construction and the necessity for a firm support for the bracketsmay, however, prevent their being spaced with the accuracy desired. Theuniversal joint comprising the-link 29 pivotedbetween the yokes 27 and 31 permits the hanger rod to accommodate any inaccuracy of the placing of the brackets. I am aware' that it has been customary'to provide fixture hangers with ball and socket joints, these joints usually being mounted at the point of suspension of the hanger. A universal mounted in this position will not, however, serve in the case of a system as here described, since any departure from verticality due to misplacement of the hanger is communicated to the entire hanger stem.

tical, thus preventing anywarpin'g of the frame.

only at'thetopof the hanger rod. that the level and angularity of the frame can beadjusted by turning the screw 23 in its threaded bushing 21.

The rectangular grid frames are hung within each unit ofthehanger frame. The grid frame itself'is of a closed" or box'section. These sections can be formed in a number of ways, one such formation being shown in Figs; 3 and 4. In this method'of construction the frame consists of 'two channels 51 and" 52 nested'together to form a closed'section of'the box girder type, the channelsb'eingfirmly secured by spot welding or otherwise to form a unitary structure. .Vertical slots 53 are-formed in the inner face of the frame at intervals corresponding to the spacing which is to be used for the elements of the louver gridl Communicating with each slot is a hole 55*formed' in the upper'horizontal webs of both channels.

The louver grid 57- of. mutually, intersecting strips joinedin the well-known. egg crate manner is prefer-'- er'ably, formed of muchthinner material than is C115.

tomary for this purpose; the'material usedbeing-not over: twenty-five' thou'sandths' ofan inch thick while it may "be as thinaas.five-thousandths of an inch. The ends of each strip are rolled as is sh'own' at the reference character' In this case the portion of the stem connecting'with the frame can always'be ver-- This" would not be'the-ca'sewith'the' universal joint positioned Itwill'be apparent '-.a= button or. ahandle'. 81: for retracting'the pin.

4. 59 and the rolled ends are inserted through the holes 55 so thatthestrips 57 project out through the slots 53. The distances between the rolled portions 59 at opposite ends of each strip are accurately determined so that the entire grid may easily he slipped into place and there is normally no tension on the frame imposed by the louver strips. Anything which. tends to skew or distort the frame will, however, impose tension on the louver strips and supply arestoring force which opposes the skew. The same is true of anything which tends to'bend or otherwise displace thelouver strips themselves. It is this which permits of the use of a lightmaterial for the louvers. Past practice has been to use open side frames withthe ends of the louvers merely projecting into a channel'shaped section so that the louvers are supported only by their ownrigidity. This has necessitated the use of material of approximately 16 B and S gage, which is fifty-one-thousandths of an inch thick and, accordingly, if made of .the same material as'used in louvers constructed in accordance with my invention weighs anywhere from about two to five times as much. The weightof the frame- Which holds thelouvers; will not be greatly different in either case, and in any-event it forms but a small fraction of the weight of the assembled grid. The lighter weight of the" grids formed in accordance with my inventionleads to saving in cost of original manufacture and in handling and shipping as well as economy of maintenance.

In order to'retain the grids in place a cover strip 60 is preferably screwed or otherwise secured over the upper webs-of the frames and the holes 55.

Fig. 5 shows a modified form of grid framewhich permits'of even cheaper and lighter construction. In this case the innerelement of the'grid frame comprises a channel 61 having an upwardly extending lip 63 from the'lower web 64 of the-channel. Slots'53 in the inner web, communicatingwith holes'55 in the upper web, are formed as before, but the box section of the frame isclosedby. a simpleangle 65, the upper'leg of which serves in place of .the, cover'plate 60'while the rear leg Partsof the frame may be joined closes the section. by'spot-welding positioned,.for-example, as indicated by the dotted circles 67 and 69.

The grid frames are suspended within the hanger frameson retractable hinge: pins 71. Pairs-of these pins are mounted at each end of'opposite' sides of the grid frame adjacent the adjoining sides, and engage holes 72' (see Fig. 2) formed in the hanger frames and positioned accurately with relation to the notches 45. The position of the hingepins is not of "criticalimportance. They shouldbe' fairly close to the ends of the grid frame sides was to make the full. area of each modular section available forwork above, but. they should also be easily reached from below. A convenient position is between the first and second-louver considered from either end of thegrid frame.

Each pin ismounted within the box section of the grid frame, in an assembly comprising a thimble 73 hav- 'mgtan' internal and external shoulder formed by construction 75: forrned' atone end, the external shoulder abutting against the inner face of the grid frame; The hlngepln' 71; iszprovi'd'ed with a collar 77 located perhaps: onequarterroft:an inch from the projecting end of .the pin WlllCh engages the hole 72 in the hanger frame.

A spring 79- abuts. against this'shoulder and the inner shoulder 75 of the'bushing 73, urging the pin outward into engagementwith the: hanger frame. The pin extends inwardlyof the frame, and may be provided with Either pair of' oppositelypositioned-pins may be considered the hinge on which the grid frame swings, while the other pair can. be considered as latches which hold it in its normal position. All' of' the hanger frame members 1 ".and 1' are provided with the holes 72. Square grid frames ing to dismount'his-ladder, andhe need not find a clearmay therefore be mounted to swing in any direction which may be most convenient for servicing; the outer units.normally will be so hungas to swing down nearest an adjoining wall while centrally positioned units will fbepositio'ned to swing so as to leave aisles clear for servlclng or to permlt aservlce'ladder to be-set in the most convenient position. One'of' the most valuable features of thev arrangement "is that a' manon aladder canswlng the louver. grid out ofthe way without havpl'ace to stack" the grids: while I the servicing is in process;

On the other hand, if it is desired to remove the grids entirely for cleaning this merely means the release of both sets of pins instead of only one.

The cleaning of the grid itself is rendered easy because of the fact that the frame section is entirely closed and there is no open channel section for dust to settle in.

While I have described in detail only the normal or standard square modular unit, it will be apparent that as in all types of modular construction fractional units may be provided. In these cases the hanger frame dimensions will normally be either one-half or one-quarter of whatever size may be adopted as the standard modular unit. Such sections require a certain amount of hand tailoring and will not usually permit the convenience of swinging on either of two 90 axes as does the square unit. It will ordinarily be found more convenient, however, to have oblong rectangular sections turn on axes in their long dimensions, and swinging in this manner can be considered a semi standard.

I consider one of the principal advantages of a light control system made in accordance with my invention to be the fact that the elements can be constructed with a greater degree of accuracy than is customary in sheet metal work of this class. All measurements and fittings can be accomplished at the factory and although the parts are shipped in disassembled form factory accuracy is automatically obtained when they are erected. The hinging of the grid units requires that the grid frames fit closely but freely within the hanger frames, with tolerances held within one-thirty-second of an inch, an accuracy not usually obtainable in sheet metal work. The various features here described all contribute to this accuracy and make the system workable.

A fairly wide choice of materials is available for construction. The hanger stem assembly will normally be of steel, but the hanger frames may be of either steel or aluminum and so may the grid frames. For the louvers themselves plastic may be added to the materials mentioned for the frames. I prefer, however, to use metal louvers, since metal is fireproof and not subject to major deformations under unusual conditions of temperature or moisture. Since the louvers can be formed of thin aluminum or thinner steel, however, the fully assembled frame can be made as light as it could be with plastic louvers of ordinary construction and this posseses the additional advantage that the light intercepted is less than when thicker and heavier construction is used. The effect of the light construction is cumulative, since lighter louvers require lighter grid frames and these, in turn, permit the use of lighter hanger frames. Using the maximum thickness of metal here suggested the percentage of directly downwardly projected light intercepted by the louvers is less than three per cent. Angularly directed light will, of course, be intercepted in part by any louver system and the proportion of this light which is made effective for actual use by reflection depends upon the finish applied to the louvers. With polished steel or aluminum up to ninety-eight per cent of the obliquely directed light may be used, whereas if the louvers are finished in dead black, as may be required for some specialized installations, the proportion of obliquely directed light made available may drop to three or four per cent. In normal applications the figures will lie somewhere between these extreme values.

Polished metal louvers will give specular reflections from some angles. The most useful finishes are matte surface aluminum and white enamel, both of which give a high degree of utilization of oblique light. Colored enamels may be used for decorative purposes or for color correction. Such modifications are not peculiar to the equipment of my invention, but the invention does permit their utilization to the fullest extent.

I claim:

1. A light control system comprising a rectangular hanger frame including at least one intermediate cross member for dividing said frame into a plurality of similar units; a grid frame fitting closely within each unit of said hanger frame; a grid of mutually intersecting louvers within said grid frame, the end of said louvers being interlocked with said grid frame whereby said grid reinforces said grid frame against distorting forces; and pairs of retractable pins mounted in the sides of said grid frame in laterally opposed positions and coacting with holes formed in said hanger frame whereon said grid frame can hinge upon retraction of all but one pair of pins.

2. A light control system in accordance with claim 1 including means for suspending said hanger frame from above comprising approximately vertical hanger rods connected at each angle of said hanger frame, means for adjusting the length of said hanger rods to level said frames, and universal joints in each of said hanger rods adjacent the junction thereof with said hanger frames, each said universal joint including two sections and a link connection therebetween, said sections and link connections constituting a part of the hanger rod and said link being pivotally attached to each section and connected to rotate at each point of pivotal attachment about axes normal to each other to relieve the frame of warping stresses when leveled.

3. A light control system comprising a rigid rectangular hanger frame including at least one cross member for dividing said frame into a plurality of similar units, and a closely fitted grid frame provided with intersecting light controlling louvers pivotally supported within each unit, the supports for said grid frame comprising pairs of laterally projecting pins mounted adjacent the ends of opposite sides of said grid frames, and springs for urging said pins outwardly into coacting holes in said hanger frames, said pins projecting inwardly into said grid frames to provide means for retracting said pins against the action of said springs to permit said grid frame to swing on an unretracted pair of pins.

4. A light control system comprising a rigid rectangular hanger frame composed of similar modular units, and a grid frame provided with intersecting louvers pivotally suspended within each unit, each of said units comprising angular corner members including a base of channel section having at least two rectangularly disposed arms and a cover plate conforming to said base and having a downwardly turned lip at the end of each arm, side members of channel section nesting within the channel section arms of said base and notched to engage said lip of said cover plate, a clamp screw passing through said base and said cover plate, and means for supporting said hanger frame engaged by said clamp screw, the chalnnel side members of adjacent units being common to oth.

5. A light control system in accordance with claim 4 including in said supporting means a universal joint, said universal joint including two sections and a link connection therebetween, and said link being pivotally attached to each section and connected to rotate at each point of pivotal attachment about axes normal to each other.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 412,713 Sayers et a1. Oct. 8, 1889 880,238 OHara Feb. 25, 1908 1,930,254 Simon Oct. 10, 1933 1,934,696 Burns Nov. 14, 1933 2,111,448 Hofiman Mar. 15, 1938 2,464,442 De Roo Mar. 15, 1949 2,564,046 Altree Aug. 14, 1951 2,568,893 Krauthamer Sept. 25, 1951 

